JPS59769A - Certificating system - Google Patents

Abstract

PURPOSE:To prevent an ID individual identification number and a pass word from being leaked easily by encrypting the ID number and the pass word for transmitting them from a terminal to a host. CONSTITUTION:The ID card 103 is inserted to a card reader 102 and the pass word is inputted from a key board 101. A suitable random word is formed from a random word generator 201 and this becomes an encoding key coding the keyed-in pass word. This random word is coded at an encoding block 202 by taking a key encoding key 205 as a key and transferred to a terminal. The coded random word is received at an input device 100 at the terminal and decoded at a decoding bolck 104 by taking the key encoding key 105 as the key. Then, the pass word keyed-in from the keyboard 101 is coded at an encoding block 106 and transferred to the host. The host decodes the pass word at a decoding block 203.

Description

[Detailed Description of the Invention] [Technical Field] The present invention provides for the identification of users at retailers, banks, computer access terminals, etc. using an ID card storing a personal identification number, etc., and a password entered by the user on a keyboard, etc. This relates to an identification system that checks whether a person is a legitimate user.

<Prior Art> Several solutions have been proposed to date for this type of identification problem. A typical example of this is that in order to receive a service, a card with a given number (personal identification number, abbreviated as ID number) recorded on it is inserted into a card reading device, and at the same time the card presenter enters a number called a PIN (PIN).
There's something that makes it look like a keyword. These ID numbers and passwords are sent to the host's central processing unit. The central processing unit has a table in which passwords corresponding to the ID numbers described above are written, and it refers to the table and retrieves the passwords corresponding to the ID numbers sent from the card reader. The user's password will be compared with the user's password, and if they match, the user can receive the service as a legitimate user. Therefore, even if the ID card is stolen, the user will not be able to receive unauthorized services unless the password is known.

However, since the ID number is recorded and the information on the ID card is transferred from the terminal side to the host side, eavesdropping becomes possible by making some kind of trick between the terminal and the host. Moreover, since the ID number is generally sent in raw form, it is possible to know the ID number. Also, as mentioned above, the password entered by the user from the keyboard is
It becomes possible to eavesdrop between the terminal and the host. Moreover, since passwords are generally sent in raw form, it is also possible to know them. Therefore, it is possible to encrypt the password on the terminal where it is entered and send it to the host, but a key is required to encrypt it. This key is on the terminal side,
It must be made commonly available on the host side, and key management becomes an issue. For example, if the key for encrypting a password is fixed and shared by both the terminal and the host, the password can be encrypted and sent from the terminal to the host. However, once the key is fixed, the strength of the encryption is maintained during the initial stage of operation, but as time increases, that strength weakens and the effectiveness of the encryption is lost.

As mentioned above, there is a strong possibility of eavesdropping between the terminal and the host, and it may be difficult to know the combination of ID number and password because the password is usually transferred in raw form. , the host may allow unauthorized access, and the resulting damage becomes a problem.EFT (Electronic
(fund transfer: % subsidiary fund transfer system), the damage will be serious.

Furthermore, even if the password is encrypted on the terminal, if the encryption key used for encryption is the same every time, the effectiveness of the encryption will be weakened, allowing unauthorized access as described above.

<Summary of the Invention> This invention encrypts the ID number and password and sends them from the terminal to the host in order to prevent the ID number and password from being easily known by tapping or eavesdropping between the terminal and the host. The encryption key that encrypts the password is generated on the host every time, and by encrypting the encryption key and sending it from the host to the terminal, the validity of the ID number and password sent by the host can be verified. Provide a system to check.

According to this invention, a personal identification number is encrypted with a password input from an input device and stored on a card.
This card is read and the encrypted personal identification number is sent to the input device, and the input device decrypts the encrypted encryption key sent from the central processing unit using a pre-stored key encryption key. The password entered above is encrypted and sent using the decrypted encryption key.

The central processing unit encrypts the encryption key generated by the random number generator using a previously stored key encryption key and sends it to the input device, and also encrypts the encrypted password sent from the input device. A table that describes the correspondence between personal identification numbers and passwords by decrypting the encrypted personal identification number sent using the decrypted password and decrypting the encrypted personal identification number using the decrypted key. Select a predetermined password from , encrypt the decrypted personal identification number above with that password, check if the result matches the encrypted personal identification number in the card, and if they match, it is valid. If there is a discrepancy, it is recognized as an unfair user.

<Example> An example of the present invention will be described with reference to the drawings. The figure only shows important functional units of the ID authentication system. These functional units include a key encryption key storage unit,
It includes a random word generator, encryption block, decryption block, table and comparison circuit. A register to temporarily store the random word generated by the random word generator, a register to temporarily store the data read from the card and transferred to the host for final comparison, and a register to temporarily store the decoded data. The table reference for the ID number, the register for temporarily storing it for subsequent encryption, and the order control by the system clock or microprocessor can be easily designed, so the explanation is omitted here.

The encryption algorithm used in this example is DES (Data Encryption), which is standardized in the United States.
-tion 5 standard). Hardware has been presented that can implement the DBS algorithm as is well known. DES is a key-controlled block encryption algorithm. Key length is standardized DE
The S algorithm has 56 pits. Tasoshi,
Since the password is entered from the keyboard in decimal digits, it is necessary to convert it into a binary key by converting it from decimal to binary, but such a conversion algorithm is well known.

The left side of the dashed-dotted line A-A' shown in the figure is composed of an input device for inputting a password on the terminal side, and a card reading device for reading a card on which a number is recorded. The right side of the dashed-dotted line B-B' is the host side. Also, the area between the dashed-dotted lines A-A' and B-B' is the communication medium between the terminal and the host, which is specifically composed of a communication line network or cable, etc. In this area, tapping, etc. It is possible to steal something.

In order to set up communication between the terminal and the host and start the operation of the authentication system, the user inserts the ID card 103 into the card reader 102 and then inputs the password using the keyboard 101.

The subsequent operations are performed automatically. ID card 10
3, the D number IDi is generally recorded using a magnetic recording method in encrypted form using the corresponding password Pwl. Expressed as a formula, it becomes Epwi (IDi). Here, E is an abbreviation for Encryption, which means an encryption operation, and is the encryption key used when PWi encrypts, and IDi enclosed in parentheses indicates the data to be encrypted. The cryptographic operation at this time uses the DES algorithm. When a key is input from the keyboard 101, activation of the authentication system on the host side is started by an appropriate signal 300 from the input device 100.

A suitable random word RNi is generated from the random word generator 201, and this becomes an encryption key for encrypting the key-in password.

Because it is dangerous to transfer the encryption key in raw form to the device,
The encryption key is encrypted and transferred. The key at this time is called a key encryption key, and must be held in common by both the host and the terminal. Key encryption key (KM) 2.05
is stored in FROM, etc., and set secretly during system construction.

On the other hand, the key encryption key (KM) 1o5 on the terminal side must also be stored in FROM, etc., and must be secretly set during system construction. The random word RN1 generated by the random word generator 201 is encrypted in the encryption block 202 using the key encryption key (KM) 205 and transferred to the terminal. That is, Ey<M
(RNi).

The input device 100 on the terminal side receives the EKM (RNi), and the decryption block 104 decodes the key encryption key (KM) 10.
It is decrypted using 5 as the key.

DKM(EKM(RNi)) →RNiko\D is D
It is an abbreviation of ``ecryption'' and means a decryption operation. The decryption operation converts the encrypted data into the original data by performing the reverse procedure of the encryption operation. Therefore, the decryption algorithm uses the DES algorithm in the same way as the encryption. Keyboard 10 earlier
1, the entered password PWl is encrypted in the encryption block 106 using the RNl decrypted in the decryption block 104 as a key, that is, ERsi(PWi)
becomes. This encrypted password is transferred to the host. On the host side, the sent E RN i (RV
i) is decoded in a decoding block 203 using the random word (RNi) generated by the random word generator 201 as a key. At this time, the random word (RN
Although not shown in the figure, i) is temporarily stored in a register or the like.

DI%N i (E+aNi(PWi) ) → PWi
Next, the data (Epwi (IDi)) of the ID card read by the card reading device 101 is transferred to the host side and temporarily stored in a register or the like, although not shown in the figure. A decryption block 204 decrypts the ID card data using the result of the decryption performed in the decryption block 203 as a key.

Dpwi(Epwi(IDi)) −+ It)iko＼
The raw ID number is decoded, and based on this ID number, the table 206 that stores a list of ID numbers and corresponding passwords created in advance is referred to, and the predetermined ID is Extract the number and the corresponding password. As a result, the ID number is encrypted in the encryption block 207 using the retrieved password as a key. If the password retrieved from table 206 is PWi, then Epwi (I
Di).

Epwi (IDi
), Epwt (IDI) sent from the card reader 102 and partially stored in the register, and the comparison circuit 20
Partial checks are performed in step 8. If they match, the relationship between the ID card and the entered password is recognized as correct, and the user can receive the host's services as a legitimate user. Furthermore, if there is a mismatch, the relationship between the ID card and the entered password will be recognized as invalid, and subsequent service from the host will be refused.

Effect> As explained above, it is possible to exploit the data transferred between the dashed-dotted lines A-A' and B-B' by tapping, etc., but the method shown in this invention According to the company, all transferred data is encrypted, making it nearly impossible to guess ID numbers and passwords from the stolen data. In addition, ID card data is encrypted with a password, and if the password is decrypted, the ID number can be deduced, so by encrypting the password with a different key for each company, it is possible to makes it more difficult to decipher.

We have made some improvements to user authentication, which is part of computer security, and have the effect of reliably preventing unauthorized access by tapping between a host and a terminal.

[Brief explanation of the drawing]

The figure is a block diagram showing an example of the authentication method according to the present invention. 101: Keyboard, 100: Input device, 102: Card reader, 103: Card, 106°202.207
: Encryption block, 104, 203. 204: Decryption block, 105, 205 = key encryption key storage unit,
201: Random word generator, 206: Table, 2
08: Comparison circuit, 300: Authentication system activation signal. Patent applicant Takashi Kusano, agent of NEC Corporation

Claims (1)

[Claims] (1) In a data processing circuit network having a terminal device and a central processing unit, a personal identification number read from a card storing a personal identification number and a password corresponding to the personal identification number are input from an input device. In an authentication method that identifies whether or not a user is a legitimate user, the input device has a mechanism for encrypting the input password, and a mechanism for encrypting the password sent from the central processing unit. a mechanism for decrypting a key; a storage unit for storing a key encryption key for decrypting the encrypted encryption key; and a mechanism for encrypting an input password with the decrypted encryption key. and transmits the encrypted password and a readout of the word stored after encrypting the personal identification number with the password to the central processing unit, and the central processing unit a storage unit that stores a key encryption key for encrypting a key, a random number generator that generates the encryption key, and a mechanism that encrypts the encryption key generated by the random number generator with the key encryption key; A mechanism for decrypting an encrypted password sent from the input device using the encryption key, and a mechanism for decrypting an encrypted personal identification number, which is a read output of the card, using the decrypted password. mechanism and the decrypted personal identification number, select a predetermined password from a table that describes the correspondence between personal identification numbers and passwords, and encrypt the decrypted personal identification number with that password. and has a mechanism to check the match between the result and the encrypted personal identification number read from the card.If the result matches the encrypted personal identification number read from the card, the user is recognized as a valid user. Authentication method that identifies unauthorized users.